Five of the 17 arrested within Iran were plotting terror attacks in the country, while the remainder were their supporters, the ministry revealed in a statement on Monday, 7 August.

"Intelligence agents succeeded in identifying and arresting a terrorist group linked to Daesh, who intended to conduct terrorist attacks in central provinces and religious cities," the statement said, referring to Isis using its Arabic name.

Those arrested from outside Iran were tracked "through intelligence-sharing with one of the intelligence services in the region," the statement added without naming the country.

The ministry further said that some of the accused were trying to smuggle arms and ammunition into the country by hiding them in home appliances, Al Jazeera reported.

Tehran has intensified its anti-terror operations following the twin attacks on 7 June on the country's parliament and the mausoleum of revolutionary founder Ayatollah Ruhollah Khomeini. Eight people were killed in the attack and scores were injured.

Dozens of suspected militants have been arrested in the country since the attack and police operations are still underway. The latest arrest was part of the same anti-terror operation.

Sunni militant group Isis has threatened more deadly attacks on Iran's Shia population. Isis does not consider Shias as true Muslims and calls them "apostates".

During their three-year rule over parts of Iraq and Syria, the jihadist group had reportedly tortured and killed many Shia Muslims, Yazidis and Christians.

Iranian police have arrested nearly 27 suspected Isis supporters from within the country and outside who were plotting attacks in the country - File photoTIMA via Reuters